Method for making a high flannel cover fabric of synthetic organic fibers



United States Patent 3,114,191 METHCB F011 MAKING A HIGH FLANNEL COVERFABRIC F SYNTHETIC QRGANHC FIBERS Robert Stuart Chapin, Wilmington,Del., assignor to E. I.

du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware No Drawing. Filed Nov. 21, 1060, Ser. No.70,423 1 Claim. (CI. 28-76) This invention relates to flannel-likefabrics devoid of wool and to methods for preparing such fabrics.

In the past, many fabrics containing fibers of acrylonitrile polymers orof polyethylene terephthalate have been blends with wool, rayon orcotton in order to incorporate properties of the latter fibers. Incertain instances the fibers which were added improved the cover, staticresistance, hole melting resistance, liveliness, comfort, etc. Forexample, to obtain satisfactory cover in fiannels, it has been necessaryto incorporate a high proportion of wool. In fact, it has been extremelydifiicult to produce satisfactory cover without using wool.

It is, therefore, an object of this invention to provide a fabric whichcontains no wool yet gives flannel cover to a degree substantially equalto that of the best Worsted or woolen fiannels of 100% wool. Otherobjects will be apparent from the description that follows.

The objects of this invention are attained by preparing a fabriccontaining at least 20% by weight of yarn spun from spontaneouslycrimpable synthetic organic fibers, such as composite filaments ofacrylonitrile polymer components (preferably a filament wherein onecomponent is substantially polyacrylonitrile and the other component isa copolymer of acrylonitrile with from about 1 to 5% of styrene sulfonicacid said copolymer containing at least 50 milliequivalents of ionizablegroups per kilogram of copolymer) differing in ionizable group contentas described in copending and coassigned patent applications Serial No.771,677 to Taylor, now Patent No. 3,038,- 237, and Serial No. 793,502 toRyan and Tichenor, now Patent No. 2,988,420, and finishing the fabric soas to develop a high nap wherein the spontaneously crirnpable fibershave become crimped to the extent of at least about 40 crimps per inch.Up to 80% of the fabric may be constituted by other synthetic organicfibers, such as fibers of polyesters of terephthalic or otherdicarboxylic acids, e.g., as polyethylene terephthalate fiber,acrylonitrile polymer fibers and/ or regenerated cellulose fibers.

It is preferred that the fabric be designed so as to be readily napped.Thus, in the case of woven fabrics relatively low twist filling yarnsshould be used. Low twist yarns should also be used in knit fabrics. Inorder to develop adequate nap and provided the desired high degree ofcrimp in the spontaneously crimpable fibers contained therein, thefabric is scoured at an elevated temperature, preferably at the boil,then heavily napped while wet and dried at about 400 F. Under theseconditions the spontaneously crimpable fibers develop more than 40crimps per inch and even as much as 50 or 60 crimps per inch. Dyeing maybe substituted for the scour, decatizing may follow the scour and beforenapping or the fabric may be dyed between the napping and drying steps.Stock dyed fibers may be used in which case it is generally desirable inorder to avoid bleeding of the dyes to scour the fabric at a lowertemperature such as at about 120 F. and pad extract or the fabric may bewet out evenly on a padder. In either case, the fabric should then besteamed at atmospheric pressure for a period of from 5 to 20 seconds andthereafter wet-napped and dried at about 400 F.

The yarns from which the fabrics of this invention are made may varywidely in composition. If the filling yarn, which is most effective inproviding the desired 3,114,191 Patented Dec. 17, 1963 cover, isentirely or preponderantly of spontaneous crimpable fibers in the formof bi-component fibers of acrylonitrile polymers then the warp may becomposed entirely of other synthetic organic fibers. Preferably,however, both filling and warp yarns are composed of at least about 30%of the spontaneously crimpable fiber, the balance being of high ornormal shrinking acrylonitrile polymer fibers, polyesterfibers ofterephthalic acid that may contain up to 15% isophthalic acid orpolyesters of other dicarboxylic acids as naphthalenedicarboxylic acidespecially the 2,6- or 2,7-isomer, with ethylene glycol or cisortrans-p-hexahydroxylylene glycol, and with or without a very minoramount of rayon. For some uses, adequate cover may be provided by usingfilling yarns comprised of only 20% of the spontaneously crimpablefibers together with other synthetic organic fibers and with the warpyarns composed entirely of other synthetic organic fibers. Large fillingyarns with relatively low twist favor napping and filling yarn countsfrom 10/ 1 cc. to 20/1 cc. with twist multi liers of 1.7 to 2.2 havebeen used with excellent results. A twill weave is preferred with loomtightness factors of from 21.4 to 28.8 since nappability depends to alarge extent on tightness. This tightness factor is that discussed anddescribed at pages 341 and 365 of Textile Fibers, Yarns, and Fabrics;Comparative Study of Their Behavior With Special Reference to Wool byErnest R. Kaswell, a text published in 1953 by Reinhold. The tightnessfactor is also discussed and defined, in terms known to those skilled inthe art, on pages 650 and 651 of volume 21 of the Textile ResearchJournal (1951) in an article entitled The Relationship Between theStructural Geometry of a Textile Fabric and Its Physical Properties-PartIII by S. Backer and S. I. Tanenhaus. Smaller and more highly twistedyarns may be used in the warp.

Thus, the fiber blend is chosen which gives the desired fiber crimppotential and a yarn and fabric construction is selected which makes thefibers available. Finishing develops the cover through napping andcrimping. The degree of cover is determined by the amount of fiberbetween the eye and the base structure. It is dependent upon the numberof fibers in the nap and the length of each. The extent of nappingcontrols the number of fibers, while the degree of crimp determines theacceptable length. Straight fibers in the nap cover very little becausethey tend to stand on end perpendicular to the fabric surface. Crimpedfibers nestle close to a fabrics surface entangling with one another. Afiber 4 mm. long becomes 2 mm. or less in length when crimped and offersabout 200 times the covering power of a fiber on end. Further, stabilityis offered through entanglement to give a uniform appearance. Straightfibers must be sheared closely to prevent shagginess. Only very slightcover is possible with a nap made up of straight fibers. Normal crimp(12-18 c.p.i.) of some spontaneously crirnpable fibers can givesatisfactory results where only light cover is desired. Cover equivalentto or greater than 100% wool is possible when crimp reaches 40 c.p.i.

It is essential in finishing the fabric that no drying step isinterposed between scouring and napping in the scour, nap, dry sequence.The degree of crimp, and hence cover, is dependent on the temperaturesof scouring and drying. Scouring temperatures may be in the range offrom to 212 F. and thedrying temperatures may vary from 250 to 400 F.Crimp frequency in the nap fibers varies directly as the temperature,and there is an increase of 1.2 c.p.i. (crimps per inch) for every 10 F.rise in either scouring or drying temperature. For the best possiblecover, scouring should be at the boil and drying should be at about 400C.

The following example is given to further illustrate the invention. Allparts and percentages are by weight unless otherwise indicated.

a Example A blend of the following fibers in the indicated proportionswas prepared for spinning by means of a picker and roll-top card: (1)30% of 2 /2 inch cut, 3 denier sideby-side bi-cornponent fibers having22.6 c.p.i. and prepared from acrylonitrile homopolyrner as onecomponent and a 96/4 copolymer of acrylonitrile with styrene sulfonicacid as the other component. The side-b -side oi-component fiber wasmade as described in the first paragraph of Example VI of copending andcoassigned application Serial No. 793,502 to Ryan and Tichenor; (2) 35%of 3 inch cut, 3 denier fibers of poly(ethylene terephthalate)containing about 2% of copolymerized S-(sodium suite) isophthalate andhaving about 20% boil-off shrinkage; (3) 30% of 3 inch cut, 3 denierfibers of the same poly (ethylene terephthalate) copolynier having about10% boil-01f shrinkage, and (4) 5% of 2 /2 inch cut, 3 denier rayon madeby the viscose process. Two yarns were spun from this blend, one for useas the filling yarn being 14/1 cotton count with 7.5 turns per inch 2twist and the other for the warp being 18/1 cotton count with 12 turnsper inch 8 twist.

A 50 inch wide 2 X 2 twill fabric was prepared in the usual way with 48warp ends per inch and with 52 filling picks per inch. The gray fabricwas scoured at the boil to desize, was wet-napped and dried at 400 B,after which it was dyed with a basic dye, dried and semi-decatized inthe conventional manner. A latent fiber bonding solution consisting ofsodium thiocyanate in water at about 1%.% concentration was padded ontothe fabric to a wet pick-up of about 100% after which the treated fabricwas dried in an oven at about 240 5., Beck scoured, again dried,sheared, pressed and finally warm blanket dccatized.

The fabric produced had excellent cover, a pleasing handle and goodsuppleness; and over-all aesthetics were considered substantially equalto fine imported woolen or Worsted fabrics, and much better than goodquality domestic fabrics, of similar construction. Furthermore,performance tests on this fabric showed unusually good crease recovery,wash-wear wrinkle resistance and very acceptable resistance to pilling.

Similarly improved fabrics were obtained by this procedure with otherfiber combinations. Satisfactory yarns are composed of at least 20%spontaneous crimpable fibers. Thus, for example yarns made up of 100%bicomponent fibers of acrylonitrile polymers, yarns made up of 60% ofthese bi-component fibers and 40% of fibers of polyesters ofterephthalic or of other dicarboxylic acid of about 10-20% boil-offshrinkage, and yarns of bi-component fibers of acrylonitrile polymers,25% acrylonitrile polymer fibers having about boilol'f shrinkage and 40%of fibers of polyesters or" terephthalic or of other dicarboxylic acidof about 10% boil-01f shrinkage are amenable to the process of theinvention. Other similar combinations of fibers will be apparent tothose skilled in the art.

What is claimed is:

A method for making a fabric devoid of wool and having high flannelcover which comprises preparing a fabric from yarn formed solely ofsynthetic organic fibers and containing about 30% by weight of staplefibers comprising side-by-side lei-component fibers whereinpolyacrylonitrile constitutes one component and a 96/ r weight basiscopolymer of acrylonitrile with styrene sulfonic acid constitutes theother component, hot scouring said fabric at the boil, wet-napping thefabric prior to any drying of the scoured fabric and then drying thefabric at about 400 F.

References Cited in the file of this patent UNITED STATES PATENTS1,526,201 Bosshard Feb. 10, 1925 2,060,664 Cohn Nov. 10, 1936 2,109,223Schmidt Feb. 22, 1938 2,268,160 Miles Dec. 30, 1941 2,303,534 FosterDec. 1, 1942 2,586,105 Speakrnan et a1 Feb. 19, 1952 2,633,624 MeyerApr. 7, 1953 FOREIGN PATENTS 228,825 Australia May 8, 1958 OTHERREFERENCES Fairchilds Dictionary of Textiles, copyrighted 1959 byFairchild Publications, Inc, New York, NY.

